There are now a number of academics studying online dating sites as they allow insights into relationship formation that are difficult to observe elsewhere in large numbers:

Like contemporary Margaret Meads, these scholars have gathered data from dating sites like Match.com, OkCupid and Yahoo! Personals to study attraction, trust, deception — even the role of race and politics in prospective romance…

“There is relatively little data on dating, and most of what was out there in the literature about mate selection and relationship formation is based on U.S. Census data,” said Gerald A. Mendelsohn, a professor in the psychology department at the University of California, Berkeley…

Andrew T. Fiore, a data scientist at Facebook and a former visiting assistant professor at Michigan State University, said that unlike laboratory studies, “online dating provides an ecologically valid or true-to-life context for examining the risks, uncertainties and rewards of initiating real relationships with real people at an unprecedented scale.”…

Of the romantic partnerships formed in the United States between 2007 and 2009, 21 percent of heterosexual couples and 61 percent of same-sex couples met online, according to a study by Michael J. Rosenfeld, an associate professor of sociology at Stanford. (Scholars said that most studies using online dating data are about heterosexuals, because they make up more of the population.)

The rest of the article has some research findings about appearance, race, and political ideology derived from studies of online dating site members.

Researchers will go wherever the research subjects are so if the people are expanding their dating pools online, that is where the research to go. It would be interesting to hear if any of these researchers have received pushback from people within their own fields who scoff at online dating sites or ask them to demonstrate the worthiness of studying online behavior.